The caps of the type indicated are, for example used in packages intended to contain pharmaceutical products, generally composed of a powder substance, contained in the cap and a liquid substance contained in the package, the dissolving of the solid product in the liquid has to be effected at the time of ingestion or consumption.
The caps known for the purpose indicated have the problem of their reduced capacity, not being suitable for other possible purposes in which relatively high quantities of substances are required to be mixed.
(In the case that a cap of this type is known, it must be cited and in particular if a record relating to these types of caps is known).